tools/perf/bench/kallsyms-parse.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Benchmark of /proc/kallsyms parsing.
   4  *
   5  * Copyright 2020 Google LLC.
   6  */
   7 #include <stdlib.h>
   8 #include "bench.h"
   9 #include "../util/stat.h"
  10 #include <linux/time64.h>
  11 #include <subcmd/parse-options.h>
  12 #include <symbol/kallsyms.h>
  13
  14 static unsigned int iterations = 100;
  15
  16 static const struct option options[] = {
  17         OPT_UINTEGER('i', "iterations", &iterations,
  18                 "Number of iterations used to compute average"),
  19         OPT_END()
  20 };
  21
  22 static const char *const bench_usage[] = {
  23         "perf bench internals kallsyms-parse <options>",
  24         NULL
  25 };
  26
  27 static int bench_process_symbol(void *arg __maybe_unused,
  28                                 const char *name __maybe_unused,
  29                                 char type __maybe_unused,
  30                                 u64 start __maybe_unused)
  31 {
  32         return 0;
  33 }
  34
  35 static int do_kallsyms_parse(void)
  36 {
  37         struct timeval start, end, diff;
  38         u64 runtime_us;
  39         unsigned int i;
  40         double time_average, time_stddev;
  41         int err;
  42         struct stats time_stats;
  43
  44         init_stats(&time_stats);
  45
  46         for (i = 0; i < iterations; i++) {
  47                 gettimeofday(&start, NULL);
  48                 err = kallsyms__parse("/proc/kallsyms", NULL,
  49                                 bench_process_symbol);
  50                 if (err)
  51                         return err;
  52
  53                 gettimeofday(&end, NULL);
  54                 timersub(&end, &start, &diff);
  55                 runtime_us = diff.tv_sec * USEC_PER_SEC + diff.tv_usec;
  56                 update_stats(&time_stats, runtime_us);
  57         }
  58
  59         time_average = avg_stats(&time_stats) / USEC_PER_MSEC;
  60         time_stddev = stddev_stats(&time_stats) / USEC_PER_MSEC;
  61         printf("  Average kallsyms__parse took: %.3f ms (+- %.3f ms)\n",
  62                 time_average, time_stddev);
  63         return 0;
  64 }
  65
  66 int bench_kallsyms_parse(int argc, const char **argv)
  67 {
  68         argc = parse_options(argc, argv, options, bench_usage, 0);
  69         if (argc) {
  70                 usage_with_options(bench_usage, options);
  71                 exit(EXIT_FAILURE);
  72         }
  73
  74         return do_kallsyms_parse();
  75 }